2023 年 33 巻 4 号 p. 222-228
Understanding the structural origin of the anomalous properties of SiO2 glass at high pressure conditions is of great interest in a wide range of scientific fields. The translational order of the silicon’s second shell is considered as the key to understand the anomalous properties. However, it has not been well identified in experiment. Here we show in situ high-pressure pair distribution function measurement of SiO2 glass to investigate the translational order of the silicon’s second shell and the tetrahedral symmetry structure. The results show that SiO2 glass consists of tetrahedral symmetry structure with separation between the first and second shells of silicon at low pressure conditions. On the other hand, at high pressures, the silicon’s second shell collapses onto the first shell, which indicates breaking of local tetrahedral symmetry in SiO2 glass under pressure.
